Biomedical subjects
Publications and source records attributed to Y Glupczynski.
We report a case of bacteremia caused by Solobacterium moorei, an anaerobic, non-sporulated Gram-positive bacillus in a patient with a multiple myeloma. The source of infection was presumably related to multiple dento-alveolar abscesses. This is the first recovery of S. moorei from blood cultures.
The incidence of anaerobic bacteraemia was studied retrospectively over 62 months at Mont-Godinne University Hospital, Yvoir, Belgium. The distribution of organisms, clinical presentations, choice of antimicrobial therapy and clinical outcome were analysed. The proportion of positive blood cultures yielding obligate anaerobes was 3.3%. The overall incidence of clinically significant anaerobic bacteraemia was 0.51 cases/1,000 patient admissions (0.61 cases/10,000 hospital-days), but was significantly higher in patients with active haematological malignancies than in other groups (5.97/10,000 vs. 0.33/10,000 hospital-days; p < 0.05). The Bacteroides fragilis group accounted for 61% of isolates, followed by Clostridium spp. (12.2%), Peptostreptococcus spp. and Leptotrichia spp. (7.3% each) and Fusobacterium spp. (4.8%). The most common risk-factors were gastrointestinal surgery (49%) and active haematological malignancies with chemotherapy and/or bone marrow graft (47%). One or more co-morbidities were present in 30 (77%) of 39 patients. The lower gastrointestinal tract (41%) and the oropharynx (23%) were the two most frequent presumed or proven sources for bacteraemia, with the origin remaining unknown in eight (20.5%) cases. The overall mortality rate (evaluated 7 days after the occurrence of bacteraemia) was 13%. Fatal outcome correlated with the severity of underlying diseases and the immunosuppressed status of the patients rather than with the causative pathogen or the effectiveness of antimicrobial therapy. Likewise, there was no difference in the mortality rate between patients with monomicrobial and polymicrobial bacteraemia. Overall, the data re-emphasise the importance of anaerobic bacteraemia, especially in patients with haematological malignancies.
Susceptibilities to 11 antimicrobial agents were determined by Etest for 93 Nocardia isolates from clinical specimens and 15 type strains belonging to different Nocardia spp. All isolates were susceptible to trimethoprim-sulphamethoxazole, amikacin and linezolid, but susceptibilities of the various Nocardia spp. to beta-lactams, aminoglycosides, ciprofloxacin and clarithromycin varied markedly. Overall, there was a good correlation between the drug resistance patterns and the species identification established by conventional phenotypic tests and 16S rDNA sequencing. Among the different species encountered, Nocardia farcinica and Nocardia brasiliensis displayed the most multiresistant profiles, with resistance to imipenem occurring mainly among isolates of N. brasiliensis and Nocardia abscessus. The species variability in susceptibility profiles and the numerous recent taxonomic changes means that in-vitro susceptibility tests may be a complementary tool for the identification of Nocardia isolates from human clinical specimens. Further studies on a larger number of species from more diverse geographical sources, including species that are found less commonly among clinical isolates, are required to validate and extend the results.
OBJECTIVES: Worldwide spread of a limited number of Panton-Valentine leucocidin (PVL) -producing methicillin-resistant Staphylococcus aureus (MRSA) clones has been reported in various communities. The objective of this study was to describe the molecular characteristics of the first PVL-positive MRSA strains isolated in Belgium. METHODS: Clinical MRSA isolates (n = 41) collected from 2002 to 2004 from Belgian patients were investigated for the PVL gene by PCR. PVL-positive isolates were genotyped by PFGE, staphylococcal cassette chromosome mec (SCCmec) typing, spa sequence typing, accessory gene regulator (agr) polymorphism and multi-locus sequence typing (MLST). Susceptibility to 14 antimicrobials was determined by the disc diffusion method. Genes encoding resistance to tetracyclines, aminoglycosides and macrolide-lincosamide-streptogramin were determined by PCR. RESULTS: Sixteen isolates carried lukS-lukF genes that encode the PVL toxin. All but one isolate were community-acquired. Three patients reported recent travel to North Africa and South America. They were associated with skin or soft tissue infections, bacteraemia and peritonitis. By molecular typing, they belonged to five genotypes: ST80-SCCmec IV, ST8-SCCmec IV, ST30-SCCmec IV, ST153-SCCmec IV and ST88-SCCmec IV. They belonged to the agr type 3 except for ST8 strains, which showed agr type 1. All isolates were susceptible to fluoroquinolones. Approximately, half of them were resistant to tetracycline, fusidic acid and kanamycin. Tetracycline-resistant strains harboured the tet(K) gene and resistance to kanamycin was associated with the aph3'-IIIa gene. The single erythromycin-resistant isolate harboured msr(A/B) genes conferring the M resistance phenotype. CONCLUSIONS: These results indicate the recent emergence and sporadic importation into Belgium of PVL-positive community-associated MRSA strains belonging to five distinct clones.
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A multicentre study was carried out in order to validate the E test in comparison with the reference agar dilution method for testing the susceptibility of Helicobacter pylori to amoxicillin, clarithromycin, and metronidazole. Ten clinical isolates and one control collection isolate ( Helicobacter pylori ATCC 43504) were tested blindly at four centres according to a uniform methodology. The E test showed excellent intra- and inter-laboratory correlations with the agar dilution method for amoxicillin and clarithromycin (>98% agreement within 2 log(2) dilution steps). For metronidazole, however, the E test revealed significantly higher minimum inhibitory concentration values (>2 log(2)) against 5 of the 10 Helicobacter pylori strains tested. Overall, neither method was found reliable for testing the susceptibility of Helicobacter pylori to metronidazole, since both tended to lack reproducibility.
Helicobacter pylori resistance to macrolides is increasing, and the need for susceptibility testing has become crucial. The only standardized method is agar dilution, which is not adapted to clinical practice. The present work aimed: (1) to optimize the technical conditions and to assess the reproducibility of the E-test and disk diffusion method for macrolides susceptibility testing of H. pylori, and (2) to assess the performances of these two phenotypic methods in detecting strains harboring a resistance mechanism to macrolides. We used 191 isolates collected in nine centers of France and Belgium. Phenotypic tests were performed on Mueller-Hinton agar supplemented with 10% horse blood, inoculated with a 2-day-old H. pylori suspension (10(8) CFU/ml), and incubated for 72 hr at 37 degrees C under microaerophilic conditions. The reproducibility studied on two randomly selected strains was better for disk diffusion than for the E-test for both clarithromycin and erythromycin. For a subset of 10 strains, the MICs of erythromycin and clarithromycin did not differ from more than one two-fold dilution when determined by E-test or agar dilution method. The breakpoints were for MICs: 1 mg/L for both clarithromycin and erythromycin and for inhibition diameters, 22 mm for clarithromycin and 17 mm for erythromycin. There was a 100% concordance between susceptibility to erythromycin and clarithromycin. However, the susceptible and resistant populations were better separated by testing erythromycin. Of 34 resistant strains, two lacked the A2142G and A2143G point mutations in 23S rRNA by PCR-RFLP. None of 15 tested sensitive strains were positive for one of these two point mutations. For clinical practice, we recommend to assess macrolide susceptibility of H. pylori by using one of these two phenotypic methods under the described technical conditions.
OBJECTIVES: Invasive pulmonary aspergillosis (IPA) is increasingly recognized as a cause of acute respiratory failure in patients with chronic obstructive pulmonary disease (COPD) treated with corticosteroids. For these patients admission in intensive care unit (ICU) is often required for life-support and mechanical ventilation. Whether this approach improves outcome is unknown. DESIGN AND SETTING: Retrospective study in a university hospital intensive care unit. PATIENTS: Between November 1993 and December 1997, 23 COPD patients were admitted in our ICU and received antifungal agents for possible IPA. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The clinical features and the outcome were reviewed. Diagnosis of IPA was classified as confirmed (positive lung tissue biopsy and/or autopsy) or probable (repeated isolation of Aspergillus from the airways with consistent clinical and radiological findings). Among the 23 patients treated for Aspergillus, 16 fulfilling these criteria for IPA were studied. Steroids had been administered at home to all patients but one and were increased during hospitalization in all. Twelve patients suffered a worsening of their bronchospasm precipitating acute respiratory failure. During ICU stay all patients required mechanical ventilation for acute respiratory failure. Although amphotericin B deoxycholate was started when IPA was suspected (0.5-1.5 mg/kg per day), all patients died in septic shock (n = 5) or in multiple-organ failure. CONCLUSIONS: The poor prognosis of intubated COPD patients with IPA, in spite of antifungal treatment suggests that further studies are required to define the limits and indications for ICU management of these patients.
A multicentre in vitro survey was carried out in 1998 in 22 European centres in order to assess the variation in the prevalence of Helicobacter pylori resistance. The susceptibility of 1,274 isolates to metronidazole, clarithromycin and amoxicillin was determined by the E test. The mean rate of resistance to metronidazole was 33.1% (95% CI, 7.5-58.9), to clarithromycin 9.9% (95% CI, 0-28.1) and to amoxicillin 0.8% (95% CI, 0-8.9). Resistance to metronidazole was significantly higher in females (P<0.001), while resistance to clarithromycin was significantly higher in children and teens (P<0.05). Resistance to both agents also tended to be higher in strains isolated from patients from southern European countries than in those isolated from patients from central or northern Europe. Overall, these results emphasize the need for further surveys of Helicobacter pylori sensitivity to antibiotics at a national and regional level.
A case of meningitis caused by group G beta-hemolytic Streptococcus (dysgalactiae, subspecies equisimilis) is reported in an 83-year-old woman. Streptococci species other than Streptococcus pneumoniae are seldom found in patients with acute bacterial meningitis, therefore, our discussion is focused on this rare organism. The question of the diagnosis of meningitis in the elderly is also addressed.
Helicobacter pylori strains from 299 patients were tested in six laboratories in different countries. Macrolide susceptibility of the strains was determined by agar dilution (17.4%) or the epsilometer test (82.6%). Mutations in the 23S ribosomal DNA (rDNA) that are associated with macrolide resistance were analyzed by PCR and reverse hybridization (PCR-line probe assay [LiPA]). This method identifies A2115G, G2141A, A2142G, A2142C, A2142T, A2143G, and A2143C mutations in the 23S rDNA. vacA s-region (s1a, s1b, s1c, and s2) and m-region (m1, m2a, and m2b) genotypes and cagA status were also determined using another PCR-LiPA system. Of the 299 strains investigated by MIC testing, 130 (43.5%) were resistant and 169 (56.5%) were susceptible to clarithromycin. Of the 130 resistant strains, 127 (97.7%) contained 23S rDNA mutations, whereas 167 (98.8%) of the 169 susceptible strains contained wild-type sequences. The predominant mutations were A2143G (45.2%) and A2142G (33.3%). Twenty-eight (19.8%) strains contained multiple 23S rDNA mutations. Only five resistant strains contained the A2142C mutation (three of these in combination with the A2142G mutation), and the A2115G, G2141A, A2142T, and A2143C mutations were not found. MICs of clarithromycin for the A2142G mutant strains were significantly higher than MICs for the A2143G strains. Although there was no significant association between 23S rDNA mutations and the vacA and cagA status, clarithromycin-susceptible strains more often contained mixed vacA genotypes, indicating the presence of multiple H. pylori strains. In conclusion, our data confirmed the very strong association between 23S rDNA mutations and macrolide resistance and showed that the PCR-LiPA permits accurate and reliable diagnosis of macrolide resistance in H. pylori.
Two national surveys were conducted to describe the incidence and prevalence of Enterobacter aerogenes in 21 Belgian hospitals in 1996 and 1997 and to characterize the genotypic diversity and the antimicrobial resistance profiles of clinical strains of E. aerogenes isolated from hospitalized patients in Belgium in 1997 and 1998. Twenty-nine hospitals collected 10 isolates of E. aerogenes, which were typed by arbitrarily primed PCR (AP-PCR) using two primers and pulsed-field gel electrophoresis. MICs of 10 antimicrobial agents were determined by the agar dilution method. Beta-lactamases were detected by the double-disk diffusion test and characterized by isoelectric point. The median incidence of E. aerogenes colonization or infection increased from 3.3 per 1,000 admissions in 1996 to 4.2 per 1000 admissions in the first half of 1997 (P < 0.01). E. aerogenes strains (n = 260) clustered in 25 AP-PCR types. Two major types, BE1 and BE2, included 36 and 38% of strains and were found in 21 and 25 hospitals, respectively. The BE1 type was indistinguishable from a previously described epidemic strain in France. Half of the strains produced an extended-spectrum beta-lactamase, either TEM-24 (in 86% of the strains) or TEM-3 (in 14% of the strains). Over 75% of the isolates were resistant to ceftazidime, piperacillin-tazobactam, and ciprofloxacin. Over 90% of the strains were susceptible to cefepime, carbapenems, and aminoglycosides. In conclusion, these data suggest a nationwide dissemination of two epidemic multiresistant E. aerogenes strains in Belgian hospitals. TEM-24 beta-lactamase was frequently harbored by one of these epidemic strains, which appeared to be genotypically related to a TEM-24-producing epidemic strain from France, suggesting international dissemination.
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Two sets of Staphylococcus aureus isolates recovered from two patients exhibited similar susceptibility profiles except for oxacillin susceptibility (MSSA) or resistance (MRSA). SMA:I macrorestriction and inter-IS256 PCR analysis showed patterns closely related to the Belgian epidemic MRSA clone 1 in each pair of MSSA/MRSA strains. Loss of one large SMA:I DNA fragment and concurrent gain of a smaller fragment in the MSSA isolates was observed. The mecA sequence present in the MRSA was absent in the MSSA variant. Therefore, in vivo deletion of the mec region may occur in some lineages of S. aureus more frequently than previously thought.
BACKGROUND: The accuracy of diagnostic tests to assess Helicobacter pylori eradication has rarely been performed. AIM: To compare the tests most commonly used for this purpose, i.e. histology, culture and (13)C urea breath test performed in centralized facilities. METHODS: Prospective study where patients were included in four centres and diagnostic tests performed centrally by biologists experienced in the field. Gastric biopsies were obtained from antrum and corpus (two for histology, two for culture from each site) 4-6 weeks after an eradication treatment. The definition of a gold standard for H. pylori-positive patients was either a positive culture or both positive histology and urea breath test results. RESULTS: Ninety-seven patients for whom data on histology, culture and (13)C urea breath test were available were included. The majority were females (60%) suffering from non-ulcer dyspepsia (52%) and having received proton-pump inhibitor-based triple therapy (62%). Forty-one per cent of the patients were H. pylori-positive according to the gold standard. The sensitivities were 90%, 95% and 92.5% and the specificities 100%, 98.2% and 100% for culture, histology and (13)C urea breath test, respectively. CONCLUSION: All the methods had excellent specificity but the sensitivity ranged between 90 and 95%. The combination of two techniques which increases the sensitivity to virtually 100% is recommended in situations where the eradication treatment requires a precise evaluation such as in clinical trials.
BACKGROUND: Indirect noninvasive methods, such as the 13C-urea breath test and serology, can be useful for the detection of Helicobacter pylori infection in children. We analyzed retrospectively the diagnostic accuracy of these two methods. PATIENTS AND METHODS: Between September, 1989, and October, 1996, H. pylori status was determined in 139 children by means of culture and histologic study of gastric biopsies. We performed 146 13C-urea breath tests and serologic assays (Cobas core; Roche). RESULTS: H. pylori infection was detected in 91 of 139 (65%) children. The 13C-urea breath test was discordant with H. pylori status in 4 of 146 tests; serology was discordant in 24 and indeterminate in 7 of 146. The 13C-urea breath test was more sensitive than serology (98% vs. 79%, P < 0.01) but comparable in specificity (96% vs. 92%). The serology yielded false negative results more often in children younger than 5 years of age (P < 0.05). CONCLUSIONS: The 13C-urea breath test is more reliable than serology for the detection of active H. pylori infection in children. Below 10 years of age serology is insufficiently sensitive for clinical purposes, whereas the 13C-urea breath test remains a reliable test.
OBJECTIVE: To study the epidemiology of Enterobacter aerogenes infections in Belgian hospitals and determine whether recent trends show an increase in incidence of E. aerogenes infections and antimicrobial resistance. METHODS: Data from the bloodstream infection component of the National Surveillance of Hospital Infections (October 1992 to September 1996 data in 45 hospitals) and from a retrospective study on E. aerogenes clinical isolates (1994 and 1995 data in 41 hospitals) were analyzed. RESULTS: E. aerogenes was recovered from clinical specimens with a mean incidence of 4.6 isolates per 10 000 patient-days and caused 0.20 bloodstream infections per 10 000 patient-days during the surveyed periods, respectively. Both rates increased significantly throughout the years. The proportion of E aerogenes within the Enterobacter genus was 35.4% in clinical isolates and 41.2% in bloodstream infections. Both proportions significantly increased over time. Incidence was not statistically different by hospital size but showed major differences between geographic regions. Resistance rates to third-generation cephalosporins and fluoroquinolones increased, and imipenem resistance emerged in several hospitals. CONCLUSIONS: This report provides evidence of an increase in E. aerogenes infections in Belgian hospitals and documents an increase in antimicrobial resistance of E. aerogenes strains. These figures provide a baseline for further surveillance data.
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